1. Field of the Invention
The present invention relates to a multi-cylinder rotary compressor mounted in, for example, an air conditioner or a freezing machine.
2. Description of the Prior Art
This kind of conventional multi-cylinder rotary compressor accommodates in a closed container an electric element and a rotary compression element, and the rotary compression element comprises: an intermediate partition plate; first and second cylinders provided on both sides of the intermediate partition plate; a rotating shaft which has eccentric portions whose rotating angles are shifted from each other 180 degrees and is connected to the electric element; rollers respectively fitted to the eccentric portions of the rotating shaft to rotate in the cylinders; and bearings for closing openings of the cylinders.
The respective cylinders are fixed on the inner wall of the closed container, and the bearings are attached to the upper and lower portions of these cylinders. In this case, there is adopted a method using two (a pair of) cylinders employed in a single-cylinder rotary compressor.
However, when two cylinders for use in the single-cylinder rotary compressor are employed as they are, the internal volume of the closed container is restricted and reduction in a quantity of oil or a space volume causes a problem of reliability. As a countermeasure, when two of the thinned cylinders are used, reduction in a compressor output can be a problem.
In order to solve the above-described technical problems in the prior art, an object of the present invention is to provide a multi-cylinder rotary compressor which can enhance the reliability by improving the compression efficiency/mechanical efficiency.
That is, the present invention provides a multi-cylinder rotary compressor for accommodating in a closed container an electric element and a rotary compression element, the rotary compression element comprising: an intermediate partition plate; first and second cylinders provided on both sides of the intermediate partition plate; a rotating shaft which has eccentric portions whose rotating angles are shifted from each other 180 degrees and is connected to the electric element; rollers fitted to the eccentric portions of the rotating shaft to rotate in the cylinders; and bearings for closing the respective openings of the cylinders, the bearings being fixed on the inner wall of the closed container, the cylinders being fixed to the bearings, a gap being formed between the respective cylinders and the inner wall of the closed container.
According to the present invention, in the multi-cylinder rotary compressor for accommodating in a closed container an electric element and a rotary compression element, the rotary compression element comprising: an intermediate partition plate; first and second cylinders provided on both sides of the intermediate partition plate; a rotating shaft which has eccentric portions whose rotating angles are shifted from each other 180 degrees and is connected to the electric element; rollers fitted to the eccentric portions of the rotating shaft to rotate in the cylinders; and bearings for closing the respective openings of the cylinders, the bearings are fixed on the inner wall of the closed container, and the cylinders are fixed to the bearings. Further, a gap is formed between the respective cylinders and the inner wall of the closed container. Therefore, the design with a relatively large internal volume of the closed container is possible, and the reliability can be enhanced. Moreover, improvement in the compression efficiency and the mechanical efficiency can be achieved with the compact multi-cylinder rotary compression element.
In particular, the compression element can be constituted by using two cylinders each having a diameter which is one size smaller for a single-cylinder rotary compressor, and use of the common parts can result in reduction in the manufacturing cost.
Further, in the multi-cylinder rotary compressor according to the present invention, the rotary compression element comprises: a vane coming into contact with the roller in the cylinder; an insertion hole formed to the cylinder; a springs inserted from the insertion hole into the cylinder to cause the vane to be in contact with the roller, a cover member for closing the opening of the insertion hole on the outer surface side of the cylinder being provided, the cover member being pressed into the cylinder.
According to the present invention, since the cover member for closing the opening of the insertion hole, which is used for inserting the spring causing the vane to be pressed to be in contact with the roller into cylinder, on the outer surface side of the cylinder is pressed into the cylinder, the structure for holding down the cover member for preventing the spring from coming off can be simplified, thereby achieving reduction in cost.
In the multi-cylindrical rotary compressor according to the present invention, the rotary compression element comprises: a vane coming into contact with the roller in the cylinder; an insertion hole formed to the cylinder; and a spring which is inserted from the insertion hole into the cylinder and causing the vane to be pressed against the roller in contact, a solid coiling portion being formed at the outer side end portion of the spring, the solid coiling portion being brought into contact with the inner wall of the closed container.
According to the present invention, since the solid coiling portion is formed at the outer side end portion of the spring for causing the vane to be pressed against the roller in contact and the solid coiling portion are brought into contact with the inner wall of the closed container, the spring can be prevented from coming off without increasing a number of components, thereby achieving considerable reduction in cost.
In the multi-cylinder rotary compressor according to the present invention, the rotary compression element comprises: a vane coming into contact with the roller in the cylinder; an insertion hole formed to the cylinder; and a spring which is inserted from the insertion hole into the cylinder and presses the vane against the roller in contact, a screw is fixed around the opening of the insertion hole, the bearing surface of the screw holding the end portion of the spring.
According to the present invention, since the end portion of the spring for pressing the vane against the roller in contact is held by the bearing surface of the screw fixed around the opening of the insertion hole, the spring can be prevented from coming off by utilizing existing parts, and hence the cost can be greatly reduced. Further, disassembly can be possible by removing the screw, thus improving the maintenance operability.
In addition, the multi-cylinder rotary compressor according to the present invention comprises a plurality of screws.
According to the present invention, since a plurality of screws are provided, the spring can be held down at multiple positions, and the spring can be hence assuredly prevented from coming off.
In the multi-cylinder rotary compressor according to the present invention, the rotary compression element comprises: a vane coming into contact with roller in the cylinder; an insertion hole formed to the cylinder; and a spring which is inserted from the insertion hole into the cylinder and presses the vane against the roller in contact, the relationship between the insertion hole and the spring being set such that the spring can be compressed and bonded in the vicinity of the opening of the insertion hole.
According to the present invention, since the relationship between the spring for pressing the vane against the roller in contact and the insertion hole is set so that the spring is compressed and bonded in the vicinity of the opening of the insertion hole, parts such as a cover or a screw for securing the spring are no longer necessary, and the cost can be greatly reduced.
Additionally, in the multi-cylinder rotary compressor according to the present invention, a spring constant of the spring from a compressed and bonded part thereof to the spring portion on the closed container side is set to be considerably higher than a spring constant from the compressed and bonded part of the spring to the vane side.
According to the present invention, since the spring constant of the spring from the compressed and bonded part thereof to the spring portion on the closed container side is set to be considerably higher than a spring constant of the spring from the compressed and bonded part thereof to the vane side, the spring expands so as to enter the insertion hole, thereby further assuredly preventing the spring from coming off.